hest (n.)

c. 1200, biheste, "a promise or pledge," from Old English behæs "a vow," perhaps from behatan "to promise" (from be- + hatan "command, call") and confused with obsolete hest "command," which may account for the unetymological -t as well as the Middle English shift in meaning to "command, injunction" (late 12c.). Both hatan and hest are from Proto-Germanic *haitanan, for which see hight.

"to know" (archaic), c. 1500, from Old English past tense of witan "to know" (cognate with German wusste, past tense of wissen "to know"); see wit. Had-I-wiste was used c. 1400-1550 in sense "regret for something done rashly or heedlessly;" see wist. Proverbial in expression Had-I-wiste cometh ever too late.

Haddywyst comyth euer to late Whan lewyd woordis beth owte y-spronge. ["Commonplace book" in Trinity College, Cambridge, c. 1500]